Today, the world was hit with the sad news of Nelson Mandela’s death. But luckily for Jennifer Hudson, she had the opportunity to study the former South African president’s life and play his ex-wife Winnie Mandela on film.

The 32-year-old actress, who graces the January cover of ESSENCE, opened up to the magazine about the challenges she faced while portraying the iconic anti-apartheid hero.

“I was so nervous about doing a good job that I started working on the accent a couple of months before I even got there,” Hudson revealed in her feature story. “So much was done to suppress Winnie’s voice, to keep her quiet…Winnie’s story needed to be told.”

The 2011 drama wasn’t her only demanding role. She went on to tell the magazine that her heroin-addicted prostitute character in The Inevitable Defeat of Mister & Pete was equally as challenging.

“It was a huge stretch for me to play Gloria,” she said. “The drugs, the tattoos, the prostitution—her life is so different from my own.”

The Grammy and Oscar Award winner said she’s able to play a wide range of characters because she’s” stronger than [she’s] ever been.”

“I spent my twenties figuring out what I wanted to do, and trying everything,” she added. “But by 30, my foundation was set. I became confident and clear about the path I wanted to take…Now I’ve really settled into myself. And I’m stronger than I’ve ever been.”